This invention relates to the production of roofing materials. More particularly, it relates to a process and roofing composition which is produced without the use of a felt or belt type backing and eliminating the usual problems associated with the felt type shingle production such as the use of saturators which can cause pollution problems and the handling of the felt based backing which can, because of its weakness, break and cause delays.
The most commonly used method in making composition asphalt roofing is to use dry felt paper as a web and carrier to receive the asphalt, filler material and granules. The process requires that this felt be unwound and immersed or sprayed with molten asphalt at 425.degree.-475.degree.F for complete saturation of the felt fibers and to fill the tiny voids in the felt sheet. The surfaces of the saturated felt are then coated with a filled asphalt material such as limestone dust and an asphalt mixture to build up the thickness and weight to various specifications, the most common being 235 lbs./roofing square. Prior to the cooling of this asphalt coating, the granules are dropped and embedded or impressed into the soft molten surface. From this point the sheet is cooled and processed into rolls or shingles of various sizes the most common being known as 12 .times. 36 square tabs. Such procedures are generally indicated in U.S. Pat. Nos. 2,112,819 and 2,893,889.
The disadvantage of this system of manufacture is the use of dry felt paper which is inherently weak and requires periodic splicing of rolls. The only purpose of the felt is to convey the molten asphalt material through the various processes. Because of its weakness and low tensile strength, it repeatedly breaks causing costly delays in manufacture. This felt requires the initial saturation to make it impervious to moisture and subsequent deterioration. The presently used saturators are large multi-roll machines with large deep tanks for immersing the dry felt into the molten asphalt. Due to the large quantities of asphalt and the circulation there is a great heat lost. Also, asphalt when heated gives off obnoxious fumes when open to the atmosphere. Hooding and fume removing equipment are necessary to get rid of these fumes. Further, the molten asphalt is also a fire and safety hazard.
In U.S. Pat. No. 2,619,675, a manufacturing procedure which does not utilize a felt base is described. However, this process requires the use of an extruder which requires high extruder forces in order to force the asphalt material from the nozzle and precise controls to assure that the extruded sheet is of uniform dimension and is self-supporting.
In the present proposed method and resulting shingle article, the saturator and all attendant equipment is eliminated as dry felt paper would not be used, eliminating splices and breaks. There would be virtually no fumes because the large open volumes of asphalt at high temperatures would be eliminated. Fire hazards now present in a saturator would be foreclosed and the resulting end product would carry a better fire rating as it would not contain dry felt paper. In addition, the present process does not require high extruding forces or precise controls for forming an extruded self-supporting sheet material.
It is an object of the present invention to provide a novel process and roofing composition wherein the usual felt base is no longer employed. It is another object of this invention to provide a process and roofing article wherein the usual saturator employed to make felt type roofing compositions is eliminated. It is still another object of this invention to provide a method and article wherein any scrap material which may result can be easily recycled. It is yet another object of this invention to provide a process for making asphalt roofing composition materials which will afford the application of molten asphalt over a moving belt surface and a material utilized for its removal from the moving belt to be further utilized in orientating cut roofing shingles into stacks for packaging and later use.